The river Lee flows through the city of Cork in two branches, which
diverge just above the city, and are reunited at the Custom House, the
central portion of the city being situated upon an island between the
two arms of the river, both of which are navigable for a short distance
above the Custom House, and are lined with quays on each side for the
accommodation of the shipping of the port.
The Anglesea bridge crosses the south arm of the river about a quarter
of a mile above its junction with the northern branch, and forms the
chief line of communication from the northern and central portions of
the city to the railway termini and deep-water quays on the southern
side of the river.
[Illustration: THE NEW ANGLESEA BRIDGE, CORK.]
The new swing bridge occupies the site of an older structure which had
been found inadequate to the requirements of the heavy and increasing
traffic, and the foundations of the old piers having fallen into an
insecure condition, the construction of a new opening bridge was taken
in hand jointly by the Corporation and Harbor Commissioners of Cork.
The new bridge, which has recently been completed, is of a somewhat
novel design, and the arrangement of the swing-span in particular
presents some original and interesting features, which appear to have
been dictated by a careful consideration of the existing local
conditions and requirements.
On each side of the river, both above and below the bridge, the quays
are ordinarily lined with vessels berthed alongside each of the quays,
and as the river is rather narrow at this point, the line of fairway for
vessels passing through the bridge is confined nearly to the center of
the river. This consideration, together with some others connected with
the proposed future deepening of the fairway, rendered it very desirable
to locate the opening span nearly in the center of the river, as shown
in the general plan of the situation, which we publish herewith. At the
same time it was necessary to avoid any encroachment upon the width of
the existing quays, which form important lines of communication for
vehicular and passenger traffic along each side of the river, and to and
from the railway stations. Again, it was necessary to preserve the full
existing width of waterway in the river itself, which is sometimes
subjected to heavy floods.
These considerations evidently precluded the construction of a central
pier and double-armed swing bridge, and on the other hand they also
precluded the construction of any solid masonry substructure for the
turntable, either upon the quay or projected into the river. To meet
these several conditions the bridge has been designed in the form of a
three-span bridge, that is to say, it is only supported by the two
abutments and two intermediate piers, each consisting of a pair of
cast-iron cylinders or columns, as shown by the dotted circles upon the
general plan.
The central opening is that which serves for the passage of vessels. The
swing bridge extends over two openings, or from the north abutment to
the southern pier, its center of revolution being situated over the
center of the northern span, and revolves upon a turntable, which is
carried upon a lower platform or frame of girders extending across the
northern span of the bridge. The southern opening is spanned by an
ordinary pair of lattice girders in line with the girders and
superstructure of the swing bridge.
We propose at an early date to publish further details of this bridge,
and the hydraulic machinery by which it is worked.
We present a perspective view of the bridge as seen from the entrance to
the exhibition building, which is situated in close proximity to the
southern end of the bridge.--_Engineering_.
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